Open AccessCauses of color in purple- and yellow- quartz
Author(s) -
Natthapong Monarumit,
Somrudee Sakkaravej,
Bhuwadol Wanthanachaisaeng,
Chatree Saiyasombat,
Wiwat Wongkokua
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1719/1/012001
Subject(s) - quartz , x ray absorption spectroscopy , absorption spectroscopy , spectroscopy , analytical chemistry (journal) , absorption (acoustics) , materials science , chemistry , mineralogy , optics , metallurgy , physics , environmental chemistry , quantum mechanics , composite material
Quartz is a variety of gemstone consisting of SiO 2 . The various colors of quartz are caused by Fe as a trace element. This study focused on the investigation of Fe oxidation states affecting colorations of purple- and yellow- quartz by X-ray absorption spectroscopy (XAS) and UV-Vis-NIR spectroscopy. The amethyst (purple- quartz) and citrine (yellow- quartz) were collected as the samples. As the XAS results, there was only Fe 3+ oxidation state on both purple-and yellow- quartz considering with the absorption energy position at the Fe K -edge compared to the Fe-oxide chemical standards i.e., FeO and Fe 2 O 3 . However, the UV-Vis-NIR absorption spectra of the purple- and yellow- quartz were different. Therefore, we propose that the coloration of purple- and yellow- quartz was caused by Fe 3+ oxidation states as the donor states at 3.59 eV and 2.28 eV with the different energy band gaps of the purple- and yellow- quartz that were 4.13 eV and 4.88 eV respectively derived from Tauc Plot method.